The properties of polyolefins are desirable for a variety of end use applications, particularly in construction, packaging, automotive and consumer markets. Compositions containing these polymers are useful as pressure sensitive adhesives for paper labels, for sealing tires and as adhesives for assembly of single ply roofing. Recently there is a trend toward the use of curable polyolefin compositions. One benefit of these curable compositions is the ability to prepare flowable solventless compositions which following application and curing exhibit properties similar to those of solvent-based adhesives.
A shortcoming of polyolefin compositions, particularly those that cure by a platinum group metal catalyzed hydrosilation reaction, is their inability to develop strong adhesion to a variety of substrates, particularly glass and certain metals, following curing under commercially feasible conditions of time and temperature. One method for remedying this deficiency is by using primer compositions or adhesion promoting additives containing one or more silanes and/or organopolysiloxanes with a plurality of silicon-bonded hydrolyzable groups and at least one organofunctional substituent that is bonded to silicon through at least one carbon atom. Primer compositions are applied to substrates to which adhesion is desired prior to application of a curable composition. Adhesion promoters are present as additional ingredients in curable composition.
U.S. Pat. No. 5,397,648 to Babu et al. describes pressure sensitive compositions for automotive masking tape. The compositions include a moisture curable alpha olefin copolymer containing hydrolyzable or condensable silyl groups.
U.S. Pat. No. 5,002,808 to Hahn and Kreil teaches blending a monomeric or oligomeric precursor of a polyolefin with a silane adhesion aid containing a benzocyclobutane group as a substituent. The monomer or oligomer preferably contains these groups.
U.S. Pat. No. 4,981,728 to Honua et al. describes a method for bonding curable organic polymer compositions to a surface using a primer. The curable composition contains 1) an organic polymer with SiX units where X is OH or a hydrolyzable group, 2) an epoxy resin, 3) a curing agent for the epoxy resin and 4) a curing agent for the organic polymer. The primer is a vinyl polymer containing Si bonded to OH or a hydrolyzable group and is a reaction product of a) a vinyl-containing polymer, preferably a poly(meth)acrylate, and b) a silane or siloxane containing hydrogen and hydrolyzable groups bonded to silicon.
U.S. Pat. Nos. 3,424,376 and 3,644,315 describe sealants for glass containing a hydrocarbon-based polymer with at least one silicon atom bonded to OH or a hydrolyzable group.
U.S. Pat. No. 4,975,488 to Ando et al. describes compositions containing 1) a vinyl polymer wherein at least one silicon atom is bonded to a hydrolyzable group and 2) a silane or disilane containing at least one OH or a hydrolyzable group.
Japanese Laid Open Application No. 01-9204 teaches reacting organic polymers containing at least one double bond or other SiH-reactive group with an organohydrogensilane or organohydrogensiloxane.
European Patent 286,218 assigned to Imperial Chemical Industries describes adhesion promoters that are organic polymers containing acid groups or precursors of acid groups and a condensable silicon-containing group.
U.S. Pat. No. 4,518,726 to Kato et al. describes metal-containing paint compositions containing a vinyl polymer with at least one silicon-bonded hydrolyzable group. A silane containing coupling agent is preferably present to retain metal powder in suspension.
Adhesion promoting additives described in the prior art typically contain at least two functional groups.
U.S. Pat. No. 5,233,006, U.S. Pat. Nos. 5,339,738, and 5,532,298 to Egger et al. describe novel polymerizable silanes containing hydrolyzable groups and acrylate or methacrylate groups. The compounds are prepared by reacting a silane containing hydrolyzable groups and an isocyanate group with a hydroxyl- or amino-substituted compound containing at least one C.dbd.C group.
U.S. Pat. Nos. 4,659,851, 4,719,262, and 4,906,686 teach reaction products of unsaturated alcohols with alkoxysilanes as adhesion promoting additives.
Reaction products of alkyl orthosilicates with saturated polyhydric alcohols are described in the prior art.
U.S. Pat. No. 2,349,338 discloses using hydrolysis products of silicic acid esters of monohydric and polyhydric alcohols, including various glycol and glycerol silicate ester derivatives as corrosion prevention additives for heat transfer liquids.
U.S. Pat. No. 2,776,307 claims organosilicon esters of the general formula (R.sup.1 O).sub.3 Si(XR.sup.2).sub.n OSi(OR.sup.3).sub.3, where R.sup.1 and R.sup.3 are saturated aliphatic hydrocarbon radicals containing from 1 to 16 carbon atoms, R.sup.2 is ethylene or propylene, X can be oxygen, and n has a value of 2,3, or 4. The compounds are used as hydraulic fluids and lubricants.
U.S. Pat. No. 2,630,446 teaches using polymeric silicates prepared from tetraalkylsilicates and polyhydric alcohols as plasticizers, lubricants, and hydraulic fluid additives.
H. G. Emblem and K. Hargreaves in an article entitled "The Preparation of Alkoxysilanes from Glycols and Glycol Monoethers", J. Inorg. Nucl. Chem., Vol.30 (3), p. 721, 1968 report various reactions useful to prepare these compounds. U.K. Patent No. 450,875 teaches a transesterification process for the manufacture of new esters of orthosilicic acid. Among the esters disclosed are those derived from polyhydric alcohols.
U.S. Pat. No. 3,029,269 teaches compounds of the general formula (RO).sub.3 SiOCR'.sub.2 (CH.sub.2).sub.n CR'.sub.2 -OSi(OR).sub.3, where n is 0-16, R' is H or a lower aliphatic radical, and R is a saturated aliphatic radical containing from 1 to 16 carbons. Suggested uses for the compounds are hydraulic fluids and other applications requiring low pour point, good viscosity and viscosity index properties, and hydrolytic stability.
U.S. Pat. No. 5,424,384, issued to Gentle and Lutz on Jun. 13, 1995 teaches curable organopolysiloxane compositions containing adhesion promoters that are reaction products of 1) a polyol that is free of ethylenic unsaturation and 2) a silane or bis-silylalkane containing at least three alkoxy groups bonded to each silicon atom. There is no teaching in the patent suggesting the utility of the disclosed adhesion promoters as adhesion promoters for polyolefins.
Japanese Patent Publication (Kokai) No. 09-316293, published on Dec. 9, 1997 describes saturated hydrocarbon polymers curable by a hydrosilation reaction. The polymers contain a silane coupling agent to improve their adhesion. Glycidoxypropyltrimethoxysilane is one of the adhesion promoters disclosed. This publication does not describe or suggest adhesion promoters that are alkoxysilanes wherein the alkoxy groups are derived from polyhydric alcohols.